This invention relates to a new and improved infeed tube for a disc-type refiner which has a well-defined compound function. Embodiments provide for the material to be refined to be smoothly and surely directed to and through the refiner inlet and, at the same time, for steam developed in the operation of the refiner to have its own separate venting path, the direction of which is that naturally developed by the steam yet substantially clear of interference with the material entering the refiner inlet. As applied the invention embodiments provide disc-type refiners which are more efficient and satisfactory in use and more economical to operate.
Disc refining is an old and well developed art, particularly in the pulp and paper industry. Much of the development in this art has been, hopefully, in the direction of greater and better utilization of the materials available to be refined and a reduction of the power required for proper refining. Improvements have been achieved in these respects but they have not by any means produced consistently satisfactory results. A basic problem which continues to exist in the art of disc refining stems from the fact that such excess steam as is normally developed in the disc refining process will backflow into the eye of the refiner and in many cases interfere with and sometimes even block the infeed of material to be refined. This not only interferes with the refining operation but reduces the quality of the refined product and increases the power and maintenance requirements for the operation of the refiner.
The relief of steam from the interior of the refiner has been effected in many ways, such as by applying a venting tube as in the case of the U.S. Pat. No. 2,561,043 or by modifying the body of a refiner disc in a manner somewhat as illustrated in the French Pat. No. 2,183,928. There have been many variations on this theme but all in the same general category, providing for a diversion of steam developed in a refiner in a manner which basically works against the natural inclination of movement of the steam. For one reason or another, the solutions of the prior art directed to the problems above noted have not proven to be fully satisfactory.
It is to a satisfactory solution of the above noted problems in the refining art that the present invention was and is directed.